The 7 of clubs thing is way too complicated to unlock, and seeing double isn't even a good joker (usually). I get that the previous iteration of Seeing Double was related to 7's, (being all played 7's give 1.5x mult), but since that has changed, I think that isn't suitable now. It also isn't very easy to stumble across, unlike most other joker unlocks
Suggestion: Unlock if last played hand of a boss blind contains a club